NTSB investigators examine damage to the engine of the Southwest Airlines plane that made an emergency landing in Philadelphia on Tuesday. Picture: NTSB handout

Southwest Airlines said Wednesday that it would speed up its existing engine inspection program after Tuesday's explosion of an engine at cruising altitude that killed one passenger.

Though Southwest CEO Gary Kelly said Tuesday night that the plane in question had undergone an inspection two days before the explosion, he said was not fully aware of the nature of that inspection or whether it included a specific inspection of that engine. Southwest flies a fleet of Boeing 737s, and all of them are equipped with the General Electric built CFM56 engine.

In a statement released Wednesday, Southwest said: "The accelerated inspections are being performed out of an abundance of caution and are expected to be completed over the next 30 days. The accelerated checks are ultrasonic inspections of fan blades of the CFM56 engines."

The passenger who died on Southwest flight 1380 from New York's LaGuardia Airport to Dallas has been identified as Jennifer Riordan, of Albuquerque, New Mexico, by her employer Wells Fargo. The plane diverted to Philadelphia after the engine exploded.

On Wednesday, birds forced a Southwest Airlines flight to make an emergency landing in Nashville, Tennessee. The plane, Flight 577, was headed from Nashville to Phoenix but had to make an emergency landing after a group of birds struck it. The plane landed safely at the Nashville International Airport. No one was injured.

The airline said that the plane was taken out of service and that passengers were being put on different flights.